Matthew Mauldon

Classifying and Assessing the Geologic Contribution to Rockfall Hazard

Rockfalls from roadcuts are a major hazard and pose problems for transportation agencies across the country. In the context of rockfall hazard management, however, no consensus exists about the role of geology in assessing rockfall hazard. This study investigates the geologic contribution to rockfall hazard through application of rockfall hazard rating systems to roadcuts in Tennessee and through additional data collection to reveal correlations between hazard characteristics and geologic attributes. The geologic character of 80 roadcuts in central and eastern Tennessee was evaluated using the Tennessee Rockfall Hazard Rating System (RHRS), which is a revision of the National Highway Institute (NHI) RHRS. Scores for both RHRSs were compared to evaluate whether the improved reproducibility of scoring for the Tennessee RHRS yielded unintended losses of scoring accuracy and sensitivity. Additional geologic attribute data beyond those used in the RHRS system were collected to determine with logistic regression analysis whether relationships among the geologic attributes, rockfall type, and block size exist. Results indicate the revised geologic component of Tennessee’s RHRS is more informative and permits description of a wider spectrum of geologic conditions thandoestheNHI version.Logisticregressionanalysis indicates rockfall type correlates to lithologic variation and the number of discontinuity sets; and block size correlates to structurally controlled rockfall, lithologic variation, mechanical layer thickness, and number of discontinuity sets. Consequently, roadcuts containing potential rockfall modes with two or more discontinuity sets, no lithologic variation, and mechanical thicknesses that exceed 1.0 m are expected to have greater Geologic Character scores.

Adaptive and Real-Time Geologic Mapping, Analysis and Design of Underground Space (AMADEUS)

This paper describes the design and implementation of an Information Technology (IT)-based system called AMADEUS for adaptive and real-time geologic mapping, analysis, and design of underground space. Advances in IT, particularly in digital imaging, data management, visualization and computation can significantly improve analysis, design and construction of underground excavations. Using IT, real-time data on geology and excavation response can be gathered during the construction using non-intrusive techniques which do not require expensive and time-consuming instrumentation. The real-time data are then used to update the geological and computational models of the excavation, and to determine the optimal rate of excavation, excavation sequence and structural support. Virtual environment (VE) systems are employed to allow virtual walk-through inside an excavation, observe geologic conditions, perform virtual tunneling operations, and investigate stability of the excavation via computer simulation.